User selected options, such as undervoltage release, shunt trip and indicating alarms for use with industrial rated molded case circuit breakers have heretofore been assembled during circuit breaker manufacture. The customer requirements were specified at the time of purchase and the custom circuit breakers having the requested accessories were obtained directly from the manufacturer. With the advent of high speed molded case industrial rated circuit breakers, it is economically advantageous for the customer to install the selected accessories in the field. The selected accessories could be purchased simultaneously with the breaker and field-installed at a substantial savings in delivery time and at minimum cost.
U.S. Pat. No. 4,013,926 describes a circuit breaker having both an electronic trip actuator and an undervoltage release mechanism. U.S. patent application Ser. No. 759,979, filed July 29, 1985, in the name of Henry Willard, discloses a common trip actuator having shunt trip and undervoltage capability. U.S. patent application Ser. No. 862,929, filed May 14, 1986, entitled "Trip Actuator For Molded Case Circuit Breakers", also describes a multi-functional trip actuator having undervoltage release facility. It is customary to assemble the trip actuators described within the aforementioned applications at the time of circuit breaker manufacture.
European patent application publication No. 138,429, entitled "Circuit Interrupter", discloses an accessory unit for thermal magnetic molded case circuit breakers which appears to be field-installable.
The purpose of the instant invention is to provide a combined trip actuator and accessory module that is specifically designed for field installation by the customer without requiring any special skills or special tools.